Endogenous endophthalmitis caused by urinary tract infection: A case report

Rationale: Endogenous endophthalmitis is a vision-threatening intraocular infection caused by hematogenous spread of infectious organisms from distant sites. Patient concerns: A 71-year-old man with a history of fever and dysuria 5 days prior to presentation presented with sudden loss of vision in his left eye. The patient had no history of ocular surgery or trauma, and ocular examination revealed a large amount of exudative plaque covering the pupil. Therefore, fundus examination was not feasible. B-scan ultrasonography revealed a dome-shaped subretinal mass with an exudative retinal detachment. Diagnosis: Endogenous endophthalmitis was diagnosed on the basis of these findings. Interventions: The patient underwent pars plana vitrectomy and the early postoperative course was favorable. Outcomes: Vitreous cultures grew gram-negative bacilli, identified as Klebsiella pneumonia. Urinalysis revealed white blood cells (++) and urinary tract infection was the only identifiable risk factor for endogenous endophthalmitis. Lessons: Urinary tract infection is an independent risk factor for endogenous endophthalmitis.


Introduction
Endogenous endophthalmitis is a vision-threatening intraocular infection caused by the hematogenous spread of infectious organisms from distant sites into the eye. [1][4] In Southeast Asia, Klebsiella pneumoniae (KP), which is often associated with a pyogenic liver abscesses (LA) and diabetes mellitus, is an important cause of endogenous endophthalmitis (3-37%). [5]Herein, we report the case of a 71-year-old man with a history of fever and dysuria who developed endogenous endophthalmitis.Additionally, we reviewed the literature on this subject.

Case presentation
A 71-year-old man presented with a two-day history of redness and sudden vision loss in his left eye.The best-corrected visual acuity was hand motion, and a noncontact tonometer revealed an intraocular pressure of 17 mm Hg in the left eye.Upon examination, the right eye showed no obvious abnormalities; however, lid edema, conjunctival chemosis, corneal edema, and a 2-mm hypopyon were observed in the left eye (Fig. 1A).Exudates were observed adhering to the posterior surface of the lens and filling the vitreous cavity through the pupillary area, making fundus examination infeasible.
The patient reported no history of ocular trauma, intravitreal injection, or ocular surgery.A detailed history revealed that the patient had fever and dysuria 5 days prior to presentation.He visited a local hospital and received intravenous fluids and antipyretics for 4 days.Furthermore, apart from urinary tract infection, he had no other risk factors for endogenous endophthalmitis (diabetes, intravenous drug use, indwelling catheter, or immunosuppression).B-scan ultrasonography revealed a dome-shaped subretinal mass with exudative retinal detachment in the left eye (Fig. 2).The fasting blood glucose level was 6.15 mmol/L, white blood cell count was 11.7 × 10 9 /L and C-reactive protein level were 56 mg/L.Urinalysis revealed positive white blood cells (++).Computed tomography and abdominal ultrasonography findings were normal.The body temperature was normal.On the basis of these findings, the patient was diagnosed with endophthalmitis and underwent vitrectomy the following day.Intraoperatively, a subretinal abscess was observed on the nasal side of the optic disc.The abscess was drained via an incision, and silicone oil was filled as a tamponading agent.Vancomycin (1 mg/0.1 mL) and ceftazidime (2.25 mg/0.1 mL) were injected into the vitreous body.A vitreous culture confirmed KP as the causative organism.Therefore, levofloxacin (0.4 g) and ceftriaxone sodium were administered intravenously once a day for 2 weeks, along with levofloxacin and tobramycin eye drops once a day for 1 month.On the second day after the operation, the vitreous cavity was filled with silicone oil when the patient lowered his head, the corneal edema was more severe than before, the anterior chamber empyema, and the remaining peep out (Fig. 1B).Fundus photography at 3 months after the operation, gray-white area    for the original abscess location, 6 months after the operation, part of the blood vessel embolism scattered in the bleeding point (Fig. 3).Two weeks after surgery, the best-corrected visual acuity was 0.05, and it improved to 0.1 at 5 months postoperatively.

Discussion
KP is a Gram-negative opportunistic bacterium that belongs to the Enterobacteriaceae family. [6]It causes a wide range of diseases, including pneumonia, urinary tract infections, bloodstream infections, and sepsis. [7]These infections are particularly problematic among neonates, elderly, and immunocompromised individuals.The co-evolution of KP in response to the challenge of an activated immune system has made it a formidable pathogen that exploits stealth strategies and actively suppresses innate immune defenses to overcome host responses and survive in tissues. [8]In East Asian countries, most cases of endogenous endophthalmitis originating from LA are caused by KP.In recent years, new challenges regarding Kp have emerged, including Hypervirulent Klebsiella pneumoniae (HvKp), which is more virulent than the classical Kp.HvKp has an increased ability to cause central nervous system infections and endophthalmitis, which require rapid recognition and site-specific treatment.HvKp usually infects community-dwelling individuals who are often healthy and induces invasive LA with specific clinical features.Approximately 80% to 90% of cases have LA as the primary focus of infection, followed by renal or lung HvKp infections.
Nearly half of the patients had diabetes mellitus.Ocular complications are common in patients with diabetes, which can lead to retinal vascular disease.Damage to the blood-ocular barrier can cause vision loss or even blindness.Patients with diabetes have decreased resistance, are prone to infection, and have poor prognosis.Although diabetes control is not significantly associated with the prognosis of endogenous endophthalmitis caused by urinary-tract infections, it remains an important risk factor, and laboratory testing is crucial for identifying the source of infection.Pathogenic bacteria can be detected in blood, urine, and vitreous humor.However, in some patients, infection is not detected in the urine or blood at an early stage of the disease, which causes a delay in diagnosis.Some researchers use 18F-fluorodeoxyglucose-positron emission tomography computed tomography for auxiliary diagnosis; however, its high cost precludes its universal clinical use. [26]n summary, urinary-tract infection is an independent risk factor for endogenous endophthalmitis, which is more common in elderly men.The prognosis is favorable in the early stages.However, when accompanied by other risk factors, the prognosis is poor.Therefore, this case has great significance for exploring the primary pathogenesis and improving the treatment of eye diseases.

Figure 1 .
Figure 1.(A)The conjunctiva was congested, highly edema, mild corneal edema, pyEMA in the anterior chamber, pupil exudation, and exudation into the fundus.(B) The vitreous cavity was filled with silicone oil.When patient lowered his head, the corneal edema was more severe than before, the anterior chamber empyema, the remaining peep out.

Figure 2 .
Figure 2. B-scan (A) and color ultrasound (B) revealed a dome-shaped subretinal mass with exudative retinal detachment.

Figure 3 .
Figure 3. Gray-white area for the original abscess location, part of the retina scattered in the bleeding point, part of the blood vessel embolism (A was 3 months after the operation; B was 6 months after the operation).

Table 1
Summary of the findings of previously published cases of endogenous endophthalmitis caused by urinary tract infection.